Effects of different alkyl chains on the performance of dye-sensitized solar cells with different electrolytes

• Propyl chains are better than hexyl chains in current generation in iodine cell.
• Hexyl chains are superior in suppression of charge recombination in cobalt cell.
• Electron lifetime of the cobalt cell is strongly dependent upon the alkyl chains.
• Effects of TBP on the performance of cells are also correlated to alkyl chains.
• An efficiency of 7.86% was achieved for the M24 sensitized cobalt cell.

To develop high-efficiency organic dyes for dye-sensitized solar cells (DSCs), a comprehensive understanding on the structure–property relationship of metal-free organic photosensitizers is warranted. To address this issue, two organic dyes (M14 and M24) featuring, respectively, propyl chains and hexyl chains have been engineered. Interestingly, it is found that the length of alkyl chains has different effects on the performance DSCs with different electrolyte (e.g., iodine electrolyte and cobalt electrolyte). Herein, we scrutinize the effects of the length of alkyl chains in terms of light-harvesting, interfacial kinetic parameters, as well as their joint contribution to the photovoltaic performance. Furthermore, the dependence of conduction band shift and electron lifetime on the concentration of 4-tert-butylpyridine (TBP) in electrolyte is also investigated.

Figure optionsDownload as PowerPoint slide